Yes, it is always listed that clots are a possible side effect of the "pill". It is a pretty long shot that you would have a problem. If, you have had a history of a clot in your past, then you probably should rethink ypour position. I used the "pill" many many yrs ago and no problems. Then I had an injury that resulted in a clot. Afer that, no more "pills" just to be on the safe side. Preventative maintenance. I have had several surgeries since and with very careful monitoring from my doctors, have done well in spite of clot history in both legs. Without the "pill" it can be uncomfortable, but tolerable. Has your doctor ever mentioned the estroderm patches to you. They do not invade the system. As long as you have no allergy to the tape, it's apparently a good alternative approach. I was allergic to the tape. have survived the "flashes" though. Good luck!